This invention relates in general to a passive electrical network for coupling radio frequency circuits, and more particularly to a network for simultaneously coupling a vehicle-mounted standard broadcast band sized whip antenna to a 40 channel Citizens band transceiver and to an AM-FM radio receiver.
Increasing interest by the general public in Citizens band radio communications has created a high demand for relatively expensive Citizens band transceivers, especially of the mobile, vehicle-mounted type. Theft of these transceivers from unattended vehicles has become epidemic.
Numerous structures and methods for discouraging such thefts have been developed, and include removable bracket-mounted transceivers, trunk stowable transceivers and anti-theft locking devices for securing the transceiver to the vehicle.
An obvious means of discouraging transceiver theft is to present to a would be thief the outward appearance of a non-transceiver equipped vehicle. Such desirable outward appearance requires that the characteristic appearance of the associated vehicle-mounted Citizens band transceiver antenna be eliminated. Such antennas are usually long, for example 108 inches (2.75m), or include easily identified loading coils required for efficient signal radiation at Citizens band frequency wavelengths. Typically, mobile transceiver antennas are mounted on the vehicle roof, trunk, or rear bumper.
One solution recognized in the art is to provide an easily removable antenna which for example can be stored within the passenger compartment or trunk of an unattended vehicle.
A more desirable solution is to utilize a permanently mounted Citizens band radio antenna disguised to present the dimensions and general appearance of a conventional cowl-mounted standard broadcast band car radio antenna. It is further desirable to utilize such a disguised antenna for simultaneous Citizens band transceiver communications and AM-FM radio receiver reception, such a single antenna system precluding the need for two separate vehicle-mounted antennas which of themselves, regardless of their individual appearance, would undesirably indicate the probable presence of a Citizens band transceiver to a would be thief.
The present invention provides such a disguised antenna system in a simple, compact, and inexpensive manner.